---
description: Execute GraphQL queries type-safe in vanilla TypeScript with GraphQL Code Generator.
---

# GraphQL Codegen with Vanilla TypeScript

GraphQL client libraries such as Apollo Client, Relay, and Urql are popular choices that allows
building powerful features for querying but come with a few drawbacks:

- **Bundle Size**: All GraphQL Client GraphQL clients come with one or more of AST parsers/
  printers, a normalized cache, network layer abstractions, and other features that can increase the
  bundle size of your application.
- **Complexity**: GraphQL clients can be complex to set up and use, especially for beginners.
  Sometimes you just want to write type-safe GraphQL operations without having to learn about
  normalized caches and network layers. Maybe this is even the reason you ended up being here.

In this guide, we will learn how to use the GraphQL Code Generator client preset with vanilla
TypeScript to generate type-safe operations and wire it up to a GraphQL server that supports the
GraphQL over HTTP protocol.

This approach is framework/runtime (React, Vue, Svelte, Node.js, Bun) agnostic and the function for
executing GraphQL operations will be a simple Type-Safe `fetch` wrapper.

## Prerequisites

For this guide, we assume that you are querying your GraphQL server from within a Browser or
Node.js/Bun/etc. environment. So you already have your Vite, Next.js, Node.js or any other vanilla
project with TypeScript setup.

This guide will work on any JavaScript environment that supports `fetch` API.

We are going to use the public [Star Wars GraphQL API](https://swapi-graphql.netlify.app/) as our
GraphQL endpoint.

## Setting up GraphQL Code Generator

The GraphQL Code Generator client preset is the preferred and built-in way to generate type-safe
operations for any GraphQL client library and also vanilla JavaScript.

To get started, install the following dependencies

- **`@graphql-codegen/cli`**: Codegen CLI for running code generation
- **`@parcel/watcher`**: Enable watch mode for the codegen CLI
- **`@graphql-codegen/schema-ast`**: Plugin for generating the schema file from the GraphQL API
  endpoint (optional if you already have a schema file)
- **`@0no-co/graphqlsp`**: TypeScript language server plugin for GraphQL auto-complete (optional)

Feel free to omit the optional dependencies if you don't need them.

```sh npm2yarn
npm install --save-dev @graphql-codegen/cli @parcel/watcher
npm install --save-dev @graphql-codegen/schema-ast
npm install --save-dev @0no-co/graphqlsp
```

After that, we can create a `codegen.ts` file in the root of our project with the following
contents:

```typescript filename="GraphQL Codegen Configuration"
import type { CodegenConfig } from '@graphql-codegen/cli'

const config: CodegenConfig = {
  schema: 'https://graphql.org/graphql/',
  documents: ['src/**/*.ts'],
  ignoreNoDocuments: true,
  generates: {
    './src/graphql/': {
      preset: 'client',
      config: {
        documentMode: 'string'
      }
    },
    './schema.graphql': {
      plugins: ['schema-ast'],
      config: {
        includeDirectives: true
      }
    }
  }
}

export default config
```

Next, we adjust our `tsconfig.json` to load `@0no-co/graphqlsp`.

```json filename="tsconfig.json"
{
  "compilerOptions": {
    "target": "ES6", // Requires ES6 and above
    "plugins": [
      {
        "name": "@0no-co/graphqlsp",
        "schema": "./schema.graphql"
      }
    ]
  }
}
```

Finally, we also need to prompt Visual Studio Code to use the local TypeScript version by creating a
`.vscode/settings.json` file with the following contents:

```json filename=".vscode/settings.json"
{
  "typescript.tsdk": "node_modules/typescript/lib",
  "typescript.enablePromptUseWorkspaceTsdk": true
}
```

## Running the Code Generator

Now we can run the following command to generate the `schema.graphql` file and the GraphQL Code
Generator client code. **Note:** We are not yet writing GraphQL operations in our codebase, we just
generate the client boilerplate code.

```sh filename="Run GraphQL Code Generator"
npx graphql-codegen --config codegen.ts
```

After running the command, you should see a new `schema.graphql` file in the root of your project
and a new folder `src/graphql` with the generated client code.

You almost never need to touch the files within `src/graphql` as they are generated and overwritten
by GraphQL Code generator.

We will now use the generated client code to write our type-safe GraphQL operations.

## Writing GraphQL Operations

Let's start GraphQL Code Generator in watch mode to generate the client code whenever we write our
code.

```sh filename="Run GraphQL Code Generator in watch mode"
npx graphql-codegen --config codegen.ts --watch
```

Next within any file in our projects `src` folder, we will import the `graphql` function from within
`src/graphql`.

```typescript filename="src/index.ts"
import { graphql } from './graphql'
```

This function allows us to define a GraphQL operation.

Thanks to the TypeScript GraphQL LSP plugin, we get auto-complete for our GraphQL operations while
writing them.

![GraphQLSP in Action, giving us auto-complete on the selection set](/assets/pages/docs/guides/vanilla-typescript/graphql-lsp-autocomplete.png)

With that, we will write a simple query operation to get the total count of people in the Star Wars
universe.

```typescript filename="src/index.ts"
import { graphql } from './graphql'

const PeopleCountQuery = graphql(`
  query PeopleCount {
    allPeople {
      totalCount
    }
  }
`)
```

As we now save the file in our editor, the GraphQL Code Generator will generate the corresponding
types, and as you hover over the `PeopleCountQuery` variable, you will see the following:

![GraphQLSP in Action, giving us auto-complete on the selection set](/assets/pages/docs/guides/vanilla-typescript/typescript-typed-result.png)

`TypedDocumentString` is a container type that holds the query operation string and also the
TypeScript type for that operations response.

We can now leverage this to build a type-safe function that executes the GraphQL operation against
our GraphQL server.

## Type-Safe GraphQL Operation Execution

We can build a simple wrapper around `fetch` that takes a `TypedDocumentString` parameter and
returns a typed response.

```typescript filename="src/graphql/execute.ts"
import type { ExecutionResult } from 'graphql'
import type { TypedDocumentString } from './graphql'

export async function execute<TResult, TVariables>(
  query: TypedDocumentString<TResult, TVariables>,
  ...[variables]: TVariables extends Record<string, never> ? [] : [TVariables]
) {
  const response = await fetch('https://graphql.org/graphql/', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/json',
      Accept: 'application/graphql-response+json'
    },
    body: JSON.stringify({
      query,
      variables
    })
  })

  if (!response.ok) {
    throw new Error('Network response was not ok')
  }

  return response.json() as ExecutionResult<TResult>
}
```

We can now use this function to execute our `PeopleCountQuery` operation.

```typescript filename="src/index.ts"
import { graphql } from './graphql'
import { execute } from './graphql/execute'

const PeopleCountQuery = graphql(`
  query PeopleCount {
    allPeople {
      totalCount
    }
  }
`)

execute(PeopleCountQuery).then(data => {
  console.log(data)
})
```

When we now hover over the `data` parameter in the `then` callback, we can see that the response is
fully typed.

![Fully typed GraphQL execution result](/assets/pages/docs/guides/vanilla-typescript/typescript-typed-result.png)

And that's it! We have successfully set up a type-safe GraphQL operation execution within a Vanilla
TypeScript project.

## Conclusion

In this article, we learned how to use GraphQL Code Generator with vanilla
TypeScript.

We set up the GraphQL Code Generator for clients and wrote a simple operation that is fully typed.

You could now integrate the `execute` function into
[TanStack Query (React Query)](https://tanstack.com/query) or SWR.

If you want to learn more about GraphQL Code Generator, check out the
[client preset documentation](/plugins/presets/preset-client).
E.g. you want to reduce bundle size by using the
[client preset babel plugin](/plugins/presets/preset-client#reducing-bundle-size)
or enable
[persisted documents](/plugins/presets/preset-client#persisted-documents)
in production for security and performance reasons.
